Carburetor



' J. w. coTTlNGHAM CARBURETOR Filed June 26, 1925 2 Sheets-Sheet l Aug. 14. 1928. I 1,680,766

J. w. coTTlNGHAM CARBURETOR Filed June 26. 1925 2 sheets-sheet 2` Patented Aug. 14, 1928.

UNITED STATES JOHN W. COTTINGHAM, F COLUMBUS, OHIO.

CARBURE'IOR.

Application led June 26, 1925. Serial No, 39,706.

This invention relates to improvements in carburetors and has for its primary object the provision of an efficient and simple carburetor constructed to automatically deliver a correctly proportioned fuel charge to the cylinders of an internal combustion engine under all conditions of operation of said engine so that eflicient operation will be obtained and at the same time high economy effected in the fuel consumed.

For` a further understanding of the invention reference is to be had to the following description and to the accompanying drawings, in which:

Figure l is a vertical sectional viewtaken through the carburetor constructed 1n accordance with the features of the present invention,

Figure 2 is a top plan view thereof,

Figure 3 is a vertical transverse sectional view on the line 3-3 of Figure 1, and

Figure 4 is a simliar view on the line 4-4 of Figure 1. y

My improved carburetor consists preferably of a casing 1, which has its lower end threaded for the reception of a base fitting Q, which is formed to comprise an air inlet conduit. 3 and a liquid hydro-carbon fuel inlet conduit 4. The fuel conduit includes a communicating pipe 5 which leads from the automatically operatingr float control mechanism 6, by means of which liquld fuel is led, in the ordinary manner common to devices of this character to the nozzle 7 of the inlet. 4 which is arranged axially and within the lower part of the casing 1.v

The vertically extending nozzle 7 of the conduit 4 includes a threaded socket 1n which is positioned a valve seating .member 8. which includes an axially extending port terminating at. its lower end in a valve seat 9, above which is arranged horizontally disposed radiating liquid outlet ports 10. To control the flow of the liquid fuel through the member 8 there is provided a longitudinally movable stem 11, which terminates at its lower end with a needle valve 12, arranged for cooperation with the seat 9. It will be seen that as the stem is moved longitudinally away from said seat fuel, it will be drawn from the ioa-t chamber 6, through the conduit 4, past the seat 9 and thence through the ports 10 into the mixing chamber of the carburetor for intimate comminglin with the air` supply.

Seats upon an annular shoulder provide ed upon the member 8 is a crown piece 13, which includes on its lower face an internal depression whose side wall is spaced from and surrounds the ports 10. Also, the crown piece 13 includes a circular and upwardly and angularly extending face 14, which is spaced from a similarly formed face 15 provided upon the nozzle 7. The member 7, immediately below the face 15 is provided with air inlet ports 16, by means of which air, obtained from the conduit 3 is drawn into the nozzle 7 and commingled with the liquid fuel which issues from the port-s 1() and supplies a propelling force which forces the fuel between the nozzle faces 14 and 15 so that the resultant mixture will issue from the open circular rim 17 of the nozzle 7.

l/Vithin the easing 1 there is mounted a piston 18, which is formed to comprise at its lower end internally disposed appropriately bulged walls 19, the latter being arranged so that the smallest diameter, as shown in Figure 1, will register with the rim 17 when the piston is in its lowermost position, and as the piston rises, in responding to engine suction, the wider diametered portions of the walls 19 will be gradually brought into registration with the rim 17 so as to produce a wider valve opening, allowing greater quantities of the vaporized fuel to pass into the casing 1 and thence to the engine. The extent of this valve opening isy regulated automatically by the operation of the associated engine and in accordance with the fuel demands of the engine. The lower edge of the piston 18 is provided with air inlet openings 20, which permit the flow of air into the carburetor to produce a combustible mixture evenv when the piston has reached its lowermost position in the easing 1.` It will berseen that air, responding to engine suction, will travel through the conduit 3, and thencethrough the openings 20, if the piston valve 18 is not elevated, and into the Venturi passage cf the piston produced by the walls 19. A portion of this air supply will pass through the ports 16, drawing the liquid fuel through' the ports lO to the open annular discharge rim 17 of the fuel conduit 4. The remainder of the air supply travels along thewalls 19 past -the rim 17 and it also creates a suction in the fuel valve which consists in the drawing of the liquid fuel b e-l tween the opposed faces 14 and of the nozzle 7 producing a vaporized or carburetted mixture suitable for delivery tothe engine cylinders. It will be seen thatas the suction of the engine is increased, due to a varying load condition, the piston valve 18 will respond to the suction and will rise to a sullicient extent, regulated automatically, to admit of a greater inflow of the fuel through the carburetor, and, conversely, as the suction decreases the piston valve recedes automatically to diminish the fuel supply.

In order to produce a more intimate commingied and vaporized fuel mixture, the upper part of the piston 18 is provided with one or more stationary screens 21 which serve to break up the liquid particles ot' the fuel and to permit generallyof their more complete vaporization. In addition to the stationary screens, the axial hub 22 ot' the piston has its lower end provided with one or more perforated fans 23, the blades of which being'so arranged as to etl'ect rotation on the part of the fan during gas travel through the carburetor. This fan, also, acts in conjunction with the vaporizing nozzle of the carburetor to break up the liquid particles contained in the fuel stream, so that such particles will more readily combine with the air to produce the desired gaseous mixture, as far as practicable, desired in hydro-carbon fuel carburation.

The stem 11 of the needle valve extends upwardly and axially from the member 8, through the hub 22 and is slidably received within a gland 24 carried in the top of the manifold fitting 25 of the carburetor. This lit-ting communicates directlyv with the open upper portion of the easing 1 and is provided with a flanged end 2G adapted for association with the inlet manifold structure (not shown) of an internal combustion engine. Also, the fitting is provided with the usual butterfly valve 27, operated manually in the usual manner. A spring 28 is in this vinstance placed around the stem 11 between the gland. 24 and the upper part of the hub This spring normally serves to force the piston valve downwardly and serves to stabilize the operation of the piston valve 1S, permitting the latter to rise and Vfall in response to the internal suction of the associated engine; I prefer to use the spring 28` but it will bc apparent that if desired this spring can be eliminated and the operation of the piston returned by gravity to a normal position. Tension on the spring may be adjusted by the movement of the gland 24. It will be seen that as the motor speed increases the piston 18, which is in rea-lityan air regulating valve, rises, allowing more air to passthe fuel nozzle, reducing the strength of the mixture to correspend to the speed of the motor. Vhen the motor is at rest, the air valve 18 descends to its lowest point. In this lowered position the fcarburetor is positioned automatically for easy starting as a. very rich fuel mixture i is initially obtain ed.

Connected with the hub 22 is an upwardly extending rod 29 which projects upwardly beyond the casing through an opening Il() providedinthe upper portion of' the fitting 25. The upper end of the rod 2S) is provided with ayoke 31 with which is pivotally connected a link 32. The upper end of the lilik is pivotally connected as at il?) to the outer end ofa bell crank lever 3G which has its intermediate portion pivoted at 3T to a bracket 58 extending from the littin;r 25. The short arm 3G of the bell crank lever has its lower end provided with a roller 3f) which is arranged to ride upon the edges Ll() of a triangular shaped cam member 41. This member ispivotcd as at l2 upon the outer end of a fulcrum arm lil and in this instance the arm 43 has pivotally connected thereto an upright screw 4.1-, carrying at its upper cnd an adjustable threaded nut 45, the spring 4G being interposed between the nut and the edge of the arm 433 so as to maintain the cam Lil in a set position ol operation. The intermediate portion of the arm 43 is provided with an opening 47' in which is slidahly re ccivcd the upper end of the stem 11, the latter heilig provided with a threaded nut 48 which bears upon. a fulcrum washer 4f), so that the oscillations of thc arm 13 would result in imparting control movement to the needle valve which is used in controlling the liquid fuel supply. The other end ot the arm is provided with an adjustable screw 50, which presses upon a guided bracket plate 51 and is supported by means ol a sliding wedge 52, carried in connection with a fitting 25. The wedge 52 is nianually operated, `and it will be seen by reciprocatingr the saine the needle valve 12 may be raised and lowered by a manual setting independently ot' the automatically operating features of the carburetor.

In the operation of the carburetor it will be seen that when an associated engine is first started a comparatively rich mixture will be imparted'yto the cylinders thereof by the present carburetor. This is due to the fact that when the engine is first started the suction created within the mixing chamber and the carburetor iscomparatively small, allowing the piston valve'to close substantially the air inlet conduit, except for the small amount of air which passes through the rcstricted openings 20. The mixture may be further enriched by operating the wedge 52, which lifts the fulcrum arm 43 and raises the needle valve 12' to more than a normal extent so as to open the ports l0. As the speed ofthe engine increases and the degree of vacuum Within the mixing chamber increases, th'episton valve 18 responds to this inuence and raises vertically from its nor mal lowered position within the mixing chamber. This causes a' greater degree of opening of the air inlet conduit, a correspondingly increased opening of the needle valve and an increase in the area between the Venturi walls 19 of the piston and the rim 17 of the fuel valve, allowing for a greater inflow of the air and fuel in proportion to the increased fuel demands of the engine. It will be noted that by the provisions of the openings Q0 the piston valve can not operate as a positive choke for arresting air flow through the carburetor.h As the piston valve continues to arise gradually and automatically Within the mixing chamber in response to accelerated engine speed it has been found that increased fuel economy in the operation of the carburetor or engine can be obtained by allowing the needle valve to restrict the inflow of the fuel but without curtailing the inflow of the air supply. This is acconr plished by the provision of the adjustable cam 41, provided on the lever 43 which is directly connected with the needle valve stem. It will be seen that as the piston valve 18 arises its movement is transferred to the bell crank lever 36 which, bv means of the roller 39, controls the oscillation of the ful crum arm 43 by engaging with the double inclined cam surface of the member 41. After the piston valve 18 has been elevated to a predetermined degree, controlled by set ting the nut 45, the roller 39 engages with the apex portion of the cam member 4l and passes to the other side of said cam member. Since the valve stem has been elevated to its maximum extent when the roller 39 is in contact with the apex portion of the cam surface 40, it follows that the movement of the roller 39, past the apex results in the lowering of the needle valve and a corresponding reduction in the flow of the fuel through the diffusing valve. Thus, the carburetor is constructed to proportion automatically the relative quantities of air and the liquid fuel so that a resultant mixture will be produced best suited to the requirements of an associated engine throughout its entire work cycle. It will be observed that the operation of the carburetor is automatic and requires no manual control other than that which may be imparted thereto by the wedge 52 when the engine is first started.

vWhat is claimed is:

l. In a carburetor for an internal combus tion engine, a casing, a fuel inlet nozzle within said casing and including an annular atomizing head, a stem for controlling fuel flow through said nozzle, a piston responsive to engine suction movably mounted within said casing, an operating member movable in unison wit-h said piston, a bell crank lever journaled exteriorly of said casing and connected with said operating mem ber, a fulcrum lever for raising and lowering said stem, said lever including a cam surface, and means provided in connection with said bell crank lever cooperative with said cam .surface to rock said fulcrum arm and effect thereby lchanges in the operating positions of said valve stem.

2. In a carburetor for an internal combustion engine, a casing, a liquid fuel nozzle in said casing, said nozzle including a reciproeating stem, a piston movably mounted within said casing and responsive to engine suctions so as to occupy varying operating positions within said casing, a rod connected with said piston and extending exteriorly of said casing, a fulcrum arm mounted on said casing and cooperative with the outer end of said valve stem to raise and lower said stem, the outer end of said arm being provided with an adjustable cam surface, and a bell crank lever pivoted upon said casing and having one end thereof connected with said rod and the other arm thereof arranged for wiping engagement with said cam surface, said cam surface being formed so that upon the raising of said piston through a predetermined distance of travel correspondino movement will be imparted to said stem and upon further travel of said piston opposed movement will be imparted to said stem.

In testimony whereof I affix my signature.

JOHN IV. COTTINGHAM. 

